Abstract: Silicon photonics is definitely a key technology in next-generation communication systems from Long-Haul networks to short reach data interconnects. To address 25 Gb/s and above applications, we present our R&D platform that uses a CMOS foundry line. The fabrication process is following a modular integration scheme which leads to a flexible platform, allowing various device combinations. Moreover this platform is associated to a device library in a PDK which includes specific photonic features and which is compatible with commercial EDA tools. Based on the maturity of this platform to build high-speed optical transceivers, we present our strategy to anticipate the next integration disruptive level by implementing multi-layer photonic circuits. Such a technology represents a new paradigm for the design of very high integration circuits that we consider first for optical interposer, and finally for optical network on chip with the convergence of photonics and electronics.